Here’s how you build a cupboard under the stairs: measure the sloped space accurately, draw out the triangular shape, build a frame from softwood, fix panels of MDF or plywood to it (usually 18 mm) and finish the whole thing off with doors, pull-out drawers or open shelves. For a DIY build, budget around 150 to 800 euros in materials, depending on the size and finish. Have a specialist make the whole thing fully to measure and you’re quickly looking at around 5,000 euros to start (Source: Elke Kast op Maat, OPMAATZAGEN.nl).
The space under a closed staircase is often the most wasted spot in the house. In this article you’ll read how to make smart use of that sloped, tapering corner, which design choices really make a difference and how to build an under-stairs unit that sits neatly against uneven walls.
Measuring the sloped space under the stairs
The biggest challenge with an under-stairs unit is the shape. The underside of the treads slopes away, the floor is sometimes not level and walls are rarely perfectly square. Measure sloppily here and you’ll be left with gaps.
An under-stairs unit, by the way, can only be built under a closed staircase. With an open staircase there’s no sloped wall to build against (Source: Elke Kast op Maat).
How do you measure a triangular space under the stairs?
Think of the space as a triangle or a trapezium. You need three pieces of information: the height on the tall side, the length along the floor and the angle of the sloped top edge.
Work like this:
- Measure the maximum height on the side where the staircase is tallest (often against the wall or the string).
- Measure the total length along the floor, from the tall side to where the staircase meets the ground.
- Measure the height from the floor to the underside of the stairs at several points (for example every 20 cm). That fixes the sloped line, even if the treads don’t run down in a straight line.
- Measure the depth from front to back. Watch out: that depth can change halfway along if the wall steps in or out.
Put all the measurements on graph paper and draw the space out to scale. That prevents calculation and cutting mistakes (Source: Hubo).
Finding the angle of the stairs
The sloped top edge follows the underside of the treads or the string. The easiest way to find that angle is with a sliding bevel (an adjustable square). Set the bevel against the floor and the sloped line, lock it and transfer the angle onto your board or frame.
Can’t catch the angle in one straight line because the treads step down? Then work with a cardboard template. Hold a large piece of cardboard against the opening, mark off the outline and use that cardboard as a template to cut your timber (Source: OPMAATZAGEN.nl).
Which layout do you choose: doors, sliding doors, drawers or pull-out units?
The shape of the unit decides how usable it becomes. You can barely reach into the low, deep corner with a normal door and fixed shelves. So choose your layout to suit the space.
| Type | Strong at | Watch out for |
|---|---|---|
| Hinged doors | Simple, cheap, plenty of access to the tall section | Take up swing room in the room; deep corner stays hard to reach |
| Sliding doors | No swing room needed, flat face | You only ever see half; runners demand precise work |
| Drawers / pull-out drawers | Full depth used, everything comes to you | Pricier because of the runners; height per drawer limited |
| Pull-out unit (roll-out) on wheels | Uses even the deepest, lowest corner fully | Needs a sturdy base construction and a level floor |
| Open shelves | Cheap, quick to make, nice for display | Dust and clutter sit on show |
Why pull-out elements make better use of the deep corner
With fixed shelves behind a door you have to bend and grope to reach the furthest, lowest corner. In practice that space stays empty.
Pull out a drawer or a complete rolling unit towards you instead, and the whole contents come out. That way you use the full depth, right into the point (Source: OPMAATZAGEN.nl).
A smart combination: pull-out drawers or a roll-out unit in the low, deep section, and hinged doors or open shelves in the tall section where you can reach standing up.
Is the consumer unit or boiler under the stairs?
Often, yes. Then extra rules apply, because you’re not allowed to box those installations in.
For the consumer unit:
- Keep the consumer unit accessible at all times. Don’t box it in permanently. Work with a removable panel or a door.
- Provide ventilation. Under NEN 2768 a closed meter cupboard needs a ventilation opening top and bottom, each with a free passage of at least 100 cm². The top opening sits no more than 20 cm below the top edge, the bottom one no more than 20 cm above the floor (Source: Meterkastcheck).
- Think about fire safety. The meter cupboard has to be part of a fire compartment and offer at least 30 or 60 minutes of resistance to fire and smoke penetration. Ventilation grilles must not weaken that fire resistance (Source: Fire Stack Element).
Is there a boiler or other heating under the stairs? That too needs an air supply and access for maintenance. When in doubt, ask your installer for the clear space the manufacturer requires.
Which material do you use for an under-stairs unit?
For an under-stairs unit at home you work with sheet material and a timber frame. The choice decides the price, the weight and the finish.
| Material | Features | Suitable for |
|---|---|---|
| MDF (painted) | Smooth, paints up crisply, no grain; but soaks up moisture in damp rooms | Doors and visible faces you want to paint evenly |
| Plywood (birch/softwood) | Strong, stable, nice edge; a bit pricier | Load-bearing faces, drawers, anything that has to take force |
| Chipboard / furniture panel | Affordable, often white melamine-faced (finished ready to use) | Carcass sides and shelves you don’t need to paint |
| Solid wood | Warm and robust, but expensive and moves with moisture | Visible accents, not for large faces |
For carcass sides and doors you usually work with 18 mm board thickness. That’s sturdy enough to bear weight and not to sag at normal cabinet widths. For back panels thinner material is often enough.
Finish
- MDF and plywood you want to paint: primer first, a light sand, then two coats of paint. That gives you an even, hard surface.
- Melamine-faced furniture panel doesn’t need painting. The foil is the finish already.
- Cut edges of MDF soak up a lot of paint. Prime those edges extra and sand in between coats.
Step by step: building a cupboard under the stairs
Here’s the complete plan. Adjust the order to suit your layout.
- Measure and draw out the space on graph paper, including the sloped corner and any steps in the wall. Decide your layout (doors, drawers, shelves).
- Check for pipes and cables. Never drill blind into walls or floor. Use a cable and pipe detector; electrical and heating runs often pass under the stairs (Source: Hubo).
- Cut the timber to size or have it cut to size. For the sloped parts use your sliding bevel or cardboard template.
- Build the frame from planed softwood, for example battens of 44 x 44 mm or 45 x 70 mm. Set the frame level and anchored against wall and floor. This frame takes up the out-of-square and gives the doors something to close against.
- Fit the sides and base. Glue the joints with wood glue and screw them tight. Glue plus screws is stronger than screws alone.
- Fit shelves or runners. Mount wall rails or shelf supports level; with chipboard keep 40 to 90 cm between the support points, depending on the thickness, so the shelf doesn’t sag (Source: Hubo). For drawers, mount the runners left and right at exactly the same height.
- Make the drawers or pull-out unit. The drawer width is the internal measurement between the sides minus twice the thickness of the runner. Soft-close runners typically carry up to around 45 kg (lengths 350 to 700 mm), heavier models up to about 75 kg (350 to 1050 mm) (Source: Ironware).
- Hang the doors. Fit the hinges and adjust them until the door sits neat and flush in the rebate.
- Finish off. Prime, sand and paint, or edge-band. Fit handles, or go handleless with push-to-open fittings for a flat face.
Making it fit precisely against uneven walls
Even a neatly built unit will show gaps if the wall bulges or the skirting board sticks out. You work those gaps away with a scribing method.
Set the unit or panel in place. Take a scriber or scribing gauge (a pen with a spacer), hold the point against the uneven wall and transfer the wall’s outline onto your panel. Saw or plane to that line. The panel now follows the exact shape of the wall.
Working against a skirting board? Measure the thickness of the skirting and cut a notch at the bottom, so the unit sits neatly over it.
Always allow a bit of clearance for moving parts. Reckon on around 2 mm all round a door, so it opens and closes neatly without binding (Source: OPMAATZAGEN.nl).
Materials, tools and costs
Tools
Tape measure, pencil, graph paper, spirit level, sliding bevel, cable and pipe detector, (plunge) circular saw or jigsaw, cordless drill, driver, sandpaper or a sander, brush or roller. For biscuit or dowel joints also a router or biscuit jointer.
Materials list
Sheet material (MDF, plywood or melamine-faced panel), planed softwood for the frame, wood glue, screws, wall plugs, hinges, drawer or cabinet runners, handles or push-to-open fittings, primer and paint (or edging tape).
Cost guide
The price depends heavily on the size and finish. The ranges below are a guide for a DIY build.
| Item | Guide |
|---|---|
| Sheet material (MDF/plywood) | 60 to 300 euros |
| Frame (softwood) | 15 to 50 euros |
| Drawer runners / cabinet runners per set | 10 to 40 euros |
| Hinges, handles, fittings | 20 to 80 euros |
| Primer and paint | 25 to 60 euros |
| DIY total | around 150 to 800 euros |
| Having it made fully to measure | from around 5,000 euros |
The pro price comes from specialist bespoke makers (Source: OPMAATZAGEN.nl, Elke Kast op Maat).
Common mistakes
- Measuring at only one point. The space under the stairs is rarely straight. Measure heights at several points.
- Drilling blind. Pipes and cables often run under the stairs. Always check with a detector.
- Closing off the deep corner with fixed shelves. You’ll never reach it again. Choose drawers or a pull-out unit there.
- Boxing in the consumer unit or boiler. Keep ventilation (100 cm² top and bottom) and access intact.
- No clearance for doors. Without 2 mm of space a door binds as soon as the timber moves.
- Not setting the frame level. A skewed frame makes every door and drawer skew.
Frequently asked questions
Can I build an under-stairs unit under an open staircase?
No. An under-stairs unit needs a closed staircase, because that’s where the sloped wall is that forms the unit. Under an open staircase there’s no back wall to build against (Source: Elke Kast op Maat).
Which timber is best for an under-stairs unit?
For crisp, painted doors, 18 mm MDF. For load-bearing faces and drawers, plywood, because it’s stronger. If you’d rather not paint, choose melamine-faced furniture panel that’s already finished.
How do I get the unit tight against an uneven wall?
Mark the shape of the wall onto your panel with a scriber or scribing gauge and saw along that line. That way the panel follows the wall exactly, with no gaps.
What does it cost to build a cupboard under the stairs?
A DIY build usually costs 150 to 800 euros in materials, depending on the size and finish. Having it made fully to measure starts around 5,000 euros.
Am I allowed to box in the consumer unit under the stairs?
You are, but it has to stay accessible and ventilated. Reckon on a ventilation opening of at least 100 cm² top and bottom, and keep the fire resistance of 30 or 60 minutes intact (Source: Meterkastcheck, Fire Stack Element).
How do I use the lowest, deepest corner of the under-stairs unit?
With pull-out elements. Pull a drawer or a rolling unit on wheels all the way out, so you can reach the full depth, even into the point under the lowest tread.
Want to get going straight away with a complete, well-thought-out plan? At Fred’s DIY Plans you’ll find worked-out plans for cupboards and other furniture to measure, with the right dimensions and materials lists, so you can confidently get started yourself.